1. Field of the Invention:
This invention relates to an endoscope having a plurality of switches in the operating part.
2. Related Art Statement:
Recently there is extensively used an endoscope (called also a scope or fiber scope) whereby organs within a body cavity can be diagnosed or inspected by inserting an elongate insertable part into the body cavity. There is used not only for industrial uses but also for medical uses an endoscope to observe or inspect an object within a boiler, machine, chemical plant pipe or device.
Further, there are also used various kinds of electronic scopes wherein such solid state imaging device as a charge coupled device (CCD) is used as an imaging means.
The above mentioned fiber scope or electronic scope is provided at the rear end of the insertable part with an operating part in which there are provided a holding part, sucking button, angle lever and various electrically controlled operating buttons. In the case of operating these buttons, the operator will hold the operating part by holding the holding part with the left hand and will operate the operating button with the left hand or right hand. However, the right hand will usually grip the insertable part and will make pushing, pulling and twisting operations and therefore the various operating buttons will be operated by the left hand holding the operating part. Further, the left hand thumb will normally operate the angle lever located on the back surface of the operating part, the middle finger, third finger and little finger will hold the holding part and therefore the various operating buttons will be operated by the left hand forefinger.
As shown in the publications of Japanese Patent Application Laid Open Nos. 182704/1983 and 197430/1988 and in U.S. Pat. No. 4,825,850, one or a plurality of operating buttons have been provided on the front surface of the operating part and have been arranged without taking their using frequency into consideration.
If the operating button can be operated only with the left hand forefinger as mentioned above, it will be necessary to arrange the operating button so as to be easily operated with the forefinger and to arrange the operating button highest in the using frequency in a position in which it can be most easily operated with the forefinger.
Also, in the above mentioned electronic endoscope, there is a case that an imaged image is recorded with a recording apparatus so as to be investigated in detail. The image is recorded in the recording apparatus generally with a still picture. Therefore, in the case of recording the image, releasing signals will be required to switch a moving picture to a still picture and to determine the timing of displaying and recording it. Such signals have been generated by switches provided in the operating part of the endoscope as described above.
However, as the kinds of the required signals increase with the forms of processing imaging signals becoming multiple, if switches are provided in response to the required signals as in the past, the number of switches provided in the operating part will also increase. Other operating buttons for sucking and the like must be provided. Thus, the operating part will become larger.
Particularly, in an endoscope for bronchial tubes, the number of operating buttons which can be provided in the operating part without reducing the operatability is limited to two. If more operating buttons than this are provided, the operatability will become very low.
For example, the left hand thumb operates the angle lever on the rear surface of the operating part and is used without being separated from the angle lever substantially during the inspection and the sucking and releasing must be made with the other fingers. Also, as the endoscope must be held, in fact, it must be able to be operated with one forefinger or with the forefinger and middle finger at most.
In the endoscope for bronchial tubes, the releasing and sucking are well used and further the freezing (stilling) is also used. Usually they are mostly used in the order of frequency of the sucking&gt;releasing&gt;freezing.
Therefore, there have been problems that, if as many buttons as the number of functions are provided, three operating buttons will be necessary, the operating part will become large and it will be very difficult to operate them without errors. That is to say, if there are three operating buttons, depending on such conditions as the position of the hand holding the operating part, the size of the hand and the length of the finger, unless the operating part is re-gripped, all the operating buttons will not be able to be operated in some case.
Particularly, if a plurality of operating buttons are arranged in the lengthwise direction of the operating part, the plurality of operating buttons will be operated with the forefinger by changing the angle with the middle finger with the third joint of the forefinger as a center. Therefore, if three or more operating buttons are arranged in the lengthwise direction of the operating part, it will be difficult to operate all the operating buttons without re-gripping the operating part.